1. Technical Field of the Invention
This invention relates to a system and method for controlling the manner of raising a vehicle window using a power drive mechanism.
2. Background Information and Description of the Related Art (Including Information Disclosed Under 37 CFR xc2xa7xc2xa71.97 and 1.98)
Published PCT application WO 98/08286, published Feb. 26, 1998, owned by Siemens A G, discloses a window motor gear drive which monitors motor current to protect against possible pinch situations in vehicle sliding roofs and windows. U.S. Pat. No. 5,801,501, issued Sep. 1, 1998, discloses a window drive motor control that monitors motor speed and slows the motor depending on window position. Published PCT application WO 00/01911, published Jan. 13, 2000, discloses a drive mechanism which mechanically limits motor torque. A system such as of U.S. Pat. No. 5,801,501 may use this type of mechanism.
There are numerous systems in the prior art for detecting situations in which a closing window should cease closing, because an obstacle may be in the way. In fact, U.S. vehicle safety standards require that vehicle power windows automatically sense certain types of obstacles, and that the closing window must automatically reopen if any of those obstacles are present. These standards are at 49 CFR xc2xa7571.118, and are part of the larger body of rules commonly referred to as the Federal Motor Vehicle Safety Standards, or FMVSS.
Often, there are two modes for closing a vehicle window. The first mode is commonly referred to as xe2x80x9cupxe2x80x9d or xe2x80x9cconventional up.xe2x80x9d All power window systems have this mode. While an xe2x80x9cupxe2x80x9d button is pressed, the window is driven up. When the button is released, the window stops. Thus, in conventional xe2x80x9cupxe2x80x9d mode, the operator ultimately decides when to start and stop closing the window.
Many vehicles, however, include a second mode commonly referred to as xe2x80x9cexpress up.xe2x80x9d When the xe2x80x9cexpress upxe2x80x9d button is pressed, the window is driven closed even if the user is no longer pressing the xe2x80x9cexpress upxe2x80x9d button. The user need not do anything more. Rather, so long as the user doesn""t press a contrary button, such as xe2x80x9cwindow downxe2x80x9d, window controls common in the art interpret an xe2x80x9cexpress upxe2x80x9d command to mean that the window should be driven all the way to its fully closed position.
Typically, a power window system will detect an obstacle based upon the function of the motor driving the window. There are many ways of doing this, such as monitoring motor current (or torque) or by monitoring motor speed, as disclosed respectively in the two prior art items referenced above.
In most of these systems, the motor detection algorithm relies upon sampling the motor attribute (current or speed) while the window is closing, and comparing that sampled attribute to a previously sampled value. If the most recent sample is noticeably different from previous samples, or if there is an unusual rate of change in these attribute sample values, then the motor may have perhaps encountered an unexpected obstacle. As such, the system reverses the motor to reopen the window.
If the starting position of the window is very close to the frame, it may be difficult for the detection algorithm to reliably discern the required changes in motor attributes. This may be because the motor will not be operating long enough to have yet come up to its full rotational speed. In this situation, the motor is still accelerating, and as such the motor attribute samples are often less reliable because of this acceleration. Thus, drawing effective comparisons between current and historical attribute samples is often difficult. These comparisons, however, are often necessary in order to perform a motor attribute trend analysis, to thereby discern the possible presence of an obstacle.
Likewise, the physical constraints of the window guides and channel may bind the window more as it approaches its final closed position. This situation may cause all attribute samples in that region to trend as if an obstacle is in the way, when in fact there may not actually be any obstacle.
All of these factors may make discerning the actual presence of an obstacle more difficult. It is therefore beneficial to have a system and method for improving the environment in which to sample the motor attributes during xe2x80x9cexpress upxe2x80x9d mode, when the starting position of the window is quite close to its final closed position. The present invention accomplishes this by determining the position of the window before beginning to close it. If the position of the window is within a predetermined proximity of its final closed position, then the xe2x80x9cexpress upxe2x80x9d command is not honored in its normal course. Instead, exception processing occurs. This exception processing may take the form of ignoring the xe2x80x9cexpress upxe2x80x9d command. The user may still close the window using the conventional xe2x80x9cupxe2x80x9d command, but he must continue pressing and holding the xe2x80x9cupxe2x80x9d button to do that. Under a different exception processing scenario, the window will be opened up to a neutral position before proceeding toward close in xe2x80x9cexpress upxe2x80x9d mode. Under a third exception process, the xe2x80x9cexpress upxe2x80x9d command will proceed to close the window from the point at which the command was received, but the window control system will heighten the sensitivity of its obstacle detection scheme.
One object of the present invention is to provide a system and method whereby a power window control can improve the likelihood that it can more readily discern an obstacle when in xe2x80x9cexpress upxe2x80x9d mode, when the starting position of that window is quite close to its final closed position. Another object is to decrease the likelihood of pinching a small object during an xe2x80x9cexpress upxe2x80x9d operation, when the window is near its closed position when the express up command is issued. A further object is to effect these objects using the sensors and controls already present in a power window system, thus alleviating the need for extra components.